1. Field of the Invention
This invention relates to paper-like receptacles and more particularly to tear tape tab openers in shrink wrap packaging.
2. Prior Art
The so-called shrink wrap packaging of articles is in common usage today. Involved is a thermo-plastic, generally an axially oriented film, which shrinks with the application of heat to tightly encompass a package. This type of packaging has become a common method of packaging everything from food products to toys. Opening these film-encased packages has led to a great and increasing interest in the use of "tear tape". My own prior patents such as U.S. Pat. Nos. 3,456,780, 3,668,061 and 3,468,412, 3,499,260 etc. generally demonstrate the current state of the art in shrink wrap film packaging. These aforementioned patents are herewith incorporated by reference.
The consumer of today has shown the greatest interest and acceptance to shrink wrap packaging in which a tear tape with tab is provided to enable the package to be more easily opened. The incorporation of a tear tape and tab in shrink wrap packaging is difficult. Prior art tear tape tabs have generally suffered from a variety of problems associated with either their manufacture or their ultimate use.
In the manufacturing of shrink wrap with tear tapes, it is necessary to produce a tear tape which, in use, will not rip off of the package unilaterally, leaving the package still wrapped. Also, the tear tape must incorporate a tab starter which will not become dislodged or broken prior to its use. Furthermore, the tear tape, when pulled, must fully open the package without lateral tearing of the film.
A further problem heretofore unsolved relates to positioning a tear tape tab on the package. It is important to have the tear tape tab at the correct place on the package to achieve the best results and this position varies from package to package depending on the overall size, bulk, configuration, etc. of the article to be wrapped. Since a user may wish to wrap a variety of different articles, flexibility in positioning the tab is essential.
As to the tab itself, it has been found that a tab-type opening formed from a horseshoe-shaped severing of the film and tape together produces an acceptable tear tape tab. U.S. Pat. No. 3,362,617 to Gieber is an example of a prior art tear tape tab of this type. However, as Gieber himself points out, the region around the edge of the cut is subject to heavy stress and to prevent stretch tearing or destruction of the wrapping film, including premature tear, Gieber recommends reinforcing around the cut. His solution is a melt cutting whereby, after a hot wire severing of film and tape, the plastic melt re-solidifies and beads around the opening.
Finally, there is a problem of adapting prior art techniques to a high speed operation, either reciprocating or continuous. Melt cutting, for example, has proven totally unsatisfactory in high speed operations because significant time must be allowed for the melt and re-solidification to take place.
All of the foregoing demonstrate the continuing need, where tear tape, shrink wrapper film is employed, for improved apparatus and methods, especially those adaptable for use in high speed application.